Trane Gas train issue

[rscamaro]

I've been working on a YCH240B3H0FB. I was told by tech services that I had an air leak on the burner side, which I found on the HSI where it enters the heat exchanger. All of the gaskets on the burner side have been ordered and will be replaced upon arrival. Initial call was for a gas leak/smell throughout store.

Here's my problem. It seems that on initial call for heat, that on the first try to light, refuses to do so. Every time afterwards it will light up and run until the end of the cycle. I thought at first that the combustion blower motor in its wye(star) configuration was bringing in too much air for it to light correctly. To remedy that I tried covering one and then 2 intake ports. No good. Finally I rewired the motor to run it in the delta config on all conditions. It started up harder but would come up to speed in short order. Gas pressure out of valve is in a negative. No matter what I did, the unit wouldn't light up on the initial call.

I'm sure that when I replace all of the gaskets and the turbulators which are pretty much rusted out, that it will start working properly again. I guess I have 2 questions on the matter.

1. Why only on the initial call for heat will the unit not light up? I've never encountered anything like this ever. Its probably caused by the air leak in the system, I was just looking for a cause.

2. Who's idea was it to use a wye(star)-delta motor for the combustion blower motor? It seems to be a bit much for such a small motor. Do these motors need a softer start or something?

...Ron

[TitleLess]

They need to pull 3.7 inches of neg , and move a lot of CFm through a large exchanger.

[shelby]

most voyageurs will leak slightly at the hot surface ignitor hole, replacing that gasket is not going to solve your raw gas smell due to intermittent ignitions, most of the time when those units start having lighting problems the gust of raw gas gets that doesn"t get lit by the hsi goes through the h/x and gets sucked into the building by the econo. First thing I would check, remove back panel check h/x cracks most importantly check the gasket on the end bell cover,(I've seen them completly disappear) then remove the combustion motor assembly and check the burner screen for a crack or dirt also check the small air diffuser screen for dirt buildup. Have you measured the hsi amperage? is it consistant through a light up? what was your gas pressure while running?

[hvac_czar]

Originally posted by shelby
then remove the combustion motor assembly and check the burner screen for a crack or dirt also check the small air diffuser screen for dirt buildup.

These are my top two picks... Also carefully check and set the gas pressure.

[rscamaro]

Thanks for the replies. When the new gaskets come in I'll make sure to check everything that was suggested except the back panel which I am unable to get to since the mall management property owner thought that it was a good idea to build a soffit on that side of the unit that even was built about a foot or so over top of the unit.

...Ron